We have continued to improve on the design of the blood centrifuge previously developed in this laboratory. The blood separation chamber is a narrow ribbon-like cell which can be either circular, spiral, helical, or a combination of the three. Tubes leading to and from the continuous flow centrifuge are continuously untwisted using a previously described principle. Through proper placement of tubes, WBC, RBC, platelets and plasma can be continuously harvested. Improvements in the centrifuge design include a dynamic self-balancing system, and special provision to exclude wear in the blood tubing during centrifugation. At present, the centrifuge operates at rotor speeds to 2500 RPM (400 G). Under those conditions, in excess of 100 ml/min of whole blood are continuously fractionated into blood and plasma components.